I suspect that the thumb safety may be a way to gain points in certain states that are unfavorable to handguns and have stringent requirements before the pistol can be sold in those states.

This is because those states that place weird requirements on guns mag cap and so forth really do not want you to have a gun in the first place and are just placing more hurdles so in Massachusetts (which is where Smith & Wesson is headquarted) you are not allowed to buy a magazine with more than a ten round cap and to make sure of that try to put ten rounds into a ten round Smith&Wesson mag, it ain't gonna happen! So you now go out and buy 10 10 round magazines so you just have to change mags more often and how long does that take?

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59,M&P9,40,40C,357,(2)45,G26

funny you mention MA. when talking about this issue....if you look at the S&W website....the MA compliant M&P 9 has NO thumb safety... and as far as the 10 shot clips....big deal if you have to change a clip...if I am carrying a 9mm and need more than 10 shots all at once, I need something more than a 9. just sayin' Product: Smith & Wesson M&P 9mm - No Thumb Safety